Unable to create a full indexation because of a "permission denied" issue


I am trying to configure urbackup on a server using Mageia with the version of urbackup with (for the moment) a single client running Mageia too. This client is a laptop which is currently NOT on the local network.
The client and the server seem to be able to talk to each other. When I manually force a backup on the client, the web gui on the server shows the client running the indexation.
BUT after a quite long time (a few hours), the client generates an error like :

2017-05-18 09:42:41: ERROR: Cannot stat “/home/xuo/nextCloud_Perso”: Permission denied (13)

nextCloud_perso is a “particular” directory which is mounted with cryptkeeper. Event the root user cannot get any read access :

$ ls -als /home/xuo/nextCloud_Perso
ls: impossible d’accéder à /home/xuo/nextCloud_Perso: Permission non accordée

The user “xuo” can access this directory.

Then the indexation fails and the backup stops.

To bypass this issue, I have added in the settings.cfg of the client :

But this does not change anything. Does anyone have any idea to solve this issue ?